It has been known that a reactive sheet-like adhesive is conventionally cured in an atmosphere of high temperature of about 100° C. The reason is that, when formed into a sheet-like shape, with temperature at about 100° C., a cured state reaches a stage of partially curing or in the course of full curing, so-called B-stage. In other words, this is because, in order to promote further curing after the progress of curing, the further curing cannot be promoted without heating at a higher temperature than a temperature given at the time of forming into the B-stage. Patent literature 1 is an invention, which relates to an adhesive sheet; however, since there is no adhesion in the adhesive sheet itself, the adhesive sheet is stuck to a supporting substrate having an adhesive layer surface on the supporting substrate. It can be considered that this is because curing is advanced in the B-stage when the adhesion is formed into a sheet-like shape. As described above, a sheet-like adhesive in the B-stage has low adhesion to an adherend and, at the same time, is required to be heated at a higher temperature than 100° C. when adhered to an adherend, and hence, when an adherend is an electronic part with deterioration by a high temperature, damage to the adherend is large. In addition, since a sheet-like adhesive in the B-stage hardly exhibits flowability when heating, bubbles may be remained when there is unevenness on an adherend.